WO 95/10420 describes a value document having a through opening punched thereinto after production thereof, said opening then being sealed on one side with a cover foil protruding beyond the opening on all sides. The cover foil is transparent at least in a partial area, so that upon an attempt to copy the value document the background will be visible and rendered accordingly by the copy machine. This permits forgeries to be easily recognized.
However, said known value document has the disadvantage that the opening produced by punching can likewise be produced by a forger. The color copy of an authentic value document no longer has the transparent area, but said area can subsequently be punched out analogously to the authentic value document and sealed again with a suitable cover foil. Forgeries are therefore difficult to recognize.